JPH0648392B2 - Positively charging non-magnetic toner for electrostatic image development - Google Patents

Description

The present invention relates to a novel toner for developing an electrostatic charge image in electrophotography, electrostatic recording, electrostatic printing and the like.

[Conventional technology]

Conventionally, as an electrophotographic method, US Pat. No. 2,297,69
No. 1, JP-B-42-23910, and JP-B-43.
No. 24748, etc., various methods are described, but in short, they are provided with a uniform electrostatic charge on the photoconductive insulating layer and are irradiated with a light image to cause static electricity. After forming an electrostatic latent image, the latent image is developed and visualized by fine powder called toner in the art, and if necessary, the powder image is transferred to paper or the like, and then fixed by heating, pressurizing, or solvent vapor. Is to do.

As a developing method applied to these electrophotographic methods,
It is roughly classified into a dry development method and a wet development method. The former is further divided into a method of using a two-component developer and a method of using a one-component developer. Depending on the type of carrier that carries the toner, the two-component developing method
Magnet brush method using iron powder carrier, beads
There are a cascade method using a carrier, a far brush method using a fur, and the like.

Further, those belonging to the one-component developing method include a powder cloud method in which toner particles are sprayed and a contact developing method (contact developing or (Also referred to as toner development), a jumping development method in which toner particles are not directly contacted with the electrostatic latent image surface, but the toner particles are charged and fly toward the latent image surface by the electric field of the electrostatic latent image, magnetic conductivity. There is a magnetic dry method in which a volatile toner is brought into contact with an electrostatic latent image surface for development.

As a toner applied to these developing methods, a fine powder in which a dye or a pigment is dispersed in a natural or synthetic resin is conventionally used. For example, particles in which a colorant is dispersed in a binder resin such as polystyrene and finely pulverized to about 1 to 30 μm are used as a toner. A magnetic toner containing magnetic particles such as magnetite is used. In the case of a system using a so-called two-component developer, the toner is usually mixed with carrier particles such as glass beads and iron powder before use. Further, the toner has a positive or negative charge depending on the polarity of the electrostatic latent image to be developed.

To retain the electric charge in the toner, it is possible to utilize the triboelectric charging property of the resin which is a component of the toner, but since the toner charging property is small in this method, the image obtained by development is easily fogged and unclear. Will be things. Therefore, in order to impart a desired triboelectric chargeability to the toner, a dye, a pigment or a charge control agent which imparts the chargeability is added.

Charge control agents known in the art today include the following:

(1) The following substances are used to control the toner to be positively charged.

Nigrosine, an azine dye containing an alkyl group having 2 to 16 carbon atoms (Japanese Examined Patent Publication No. 42-1627), a basic dye (for example, CIBasic Yellow2 (CI41000), CIBasic Yellow
3, CIBasic Red 1 (CI45160), CIBasic Red 9 (CI4
2500), CIBasic Violet 1 (CI42535), CIBasic Viol
et 3 (CI42555), CIBasic Violet 10 (CI45170), C.
I.Basic Violet 14 (CI42510), CIBasic Blue 1 (CI
42025), CIBasic Blue3 (CI51005), CIBasic Blue 5
(CI42140), CIBasic Blue 7 (CI42595), CIBasic
Blue 9 (CI52015), CIBasic Blue 24 (CI52030), C.
I.Basic Blue 25 (CI52025), CIBasic Blue 26 (CI4
4045), CIBasic Green 1 (CI42040), CIBasic Green
4 (CI42000), CI42510, CI45170, etc. lake pigments of these basic dyes, (as a laker, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, pheridianide , Ferrocyanide, etc.), CISolvent
Black 3 (CI26150), Hansa Yellow G (CI11680), C.
I.Mordlant Black 11, CI Pigment Black 1, Gilsonite, Asfarto, etc.

Quaternary ammonium salts such as benzolmethyl-hexadecylammonium chloride, decyl-trimethylammonium chloride, organic complex compounds such as dibutyltin oxide, metal salts of higher fatty acids, glass, mica, inorganic fine powders of zinc oxide, EDTA, acetylacetone Polyamine resins such as amino group-containing vinyl polymers and amino group-containing condensed polymers, such as the metal complexes of.

(2) The following substances control the toner to be negatively charged. Japanese Examined Patent Publication Nos. 41-20153 and 43-2758
6, metal complex salts of monoazo dyes described in JP-A Nos. 4-6387, 45-28478 and the like, JP-A-50-1.
Dyes and pigments such as nitrohumic acid and its salts or CI14645 described in No. 33338, No. 55-42752, No. 58-41508, No. 58-7384, No. 58-7385 Metallic complexes of salicylic acid, naphthoic acid, dicarboxylic acid such as Co, Cr, and Fe, sulfonated copper phthalocyanine pigments, nitro groups, halogen-incorporated styrene oligomers, chlorinated paraffins, and melamine resins.

Many of these charge control agents are derived from face wash,
Generally, the structure is complicated and most of them have strong coloring properties.

Among the newly proposed ones, there are some that are of a different system from these, but none of them are superior in overall performance to those of the facial cleansing system, and there are still examples of dyes being used while still unsatisfactory. Mostly.

These are usually added to a thermoplastic resin, thermally melt-dispersed, finely pulverized, and adjusted to an appropriate particle size as needed before use.

However, these dyes as charge control agents have a complicated structure, the properties are not constant, and the stability is poor. Further, decomposition during thermal kneading, mechanical shock, friction, changes in temperature and humidity conditions, and the like easily cause decomposition or deterioration, and a phenomenon in which charge controllability is deteriorated easily occurs.

Therefore, when a toner containing these dyes as a charge control agent is developed using a copying machine, the charge control agent may be decomposed or deteriorated as the number of times of copying increases, and the toner may deteriorate during its durability.

Further, since it is extremely difficult to uniformly disperse these charge control agents in the thermoplastic resin, there is a fatal defect that the triboelectric charge amount between toner particles obtained by pulverization causes a difference. is doing. For this reason, various methods have been conventionally used for more uniform dispersion. For example, a basic nigrosine dye is used in the form of a salt with a higher fatty acid in order to improve the compatibility with a thermoplastic resin, but the unreacted fatty acid or a dispersion product of the salt is often used.
It is exposed on the surface of the toner and contaminates the carrier or the toner carrier, which causes deterioration of the fluidity of the toner, fogging, and deterioration of image density. Alternatively, in order to improve the dispersion of these charge control agents in the resin, a method of mechanically pulverizing and mixing the charge control agent powder and the resin powder in advance and then hot-melt kneading is used. However, the original poor dispersion cannot be avoided, and in the current situation, sufficient charge uniformity for practical use has not yet been obtained.

In addition, most of the substances generally known as charge control agents have a dark color and cannot be contained in a vivid chromatic color developer.

In addition, many charge control agents are hydrophilic, and due to poor dispersion in these resins, when melt-kneaded and then crushed,
The dye is exposed on the toner surface. Therefore, when the toner is used under high humidity conditions, these charge control agents are hydrophilic, so that a high quality image cannot be obtained.

Thus, when the conventional charge control agent is used in the toner,
Electric charges generated on the surface of the toner particles vary between the toner particles or between the toner carriers or between the toner carrier such as the toner and the sleeve, which may cause development fog, toner scattering, carrier contamination, etc. Failures are likely to occur. In addition, this obstacle appears as a remarkable phenomenon when a large number of copies are piled up, and is substantially unsuitable for a copying machine.

Further, under high humidity conditions, the transfer efficiency of the toner image is remarkably reduced, and many of them cannot be used. Even when the toner is stored for a long time even at room temperature and normal humidity, it is used. Instability of the charge control agent often causes alteration and renders it unusable due to poor chargeability.

Furthermore, when a conventional charge control agent is used in a toner, the charge control agent adheres to the surface of the photoreceptor or the adhesion of the toner due to long-term use, which adversely affects the latent image formation,
(Filming phenomenon), scratches on the surface of the photoconductor or cleaning member such as a cleaning blade, or acceleration of abrasion of the member often cause adverse effects on the cleaning process of the copying machine.

Furthermore, when a conventional charge control agent is used in toner, there are not a few that greatly affect the heat melting characteristics of the toner and deteriorate the fixing performance. In particular, it deteriorates the high temperature offset performance and increases the sticking property of the transfer paper to the roller during heat roll fixing. There are some things that reduce the durability life of the roller.

As described above, the conventional charge control agents have many drawbacks,
There is a strong demand in the art to improve these,
Although many improved techniques have been proposed so far, the fact is that none of them has been found to be totally satisfactory in practical use.

[Problems to be solved by the invention]

An object of the present invention is to provide a new technique of toner charge control that overcomes such drawbacks.

An object of the present invention is to provide a stable triboelectric charge amount between toner particles, between toner and carrier, between a toner and a toner carrier such as a sleeve in the case of one-component development, and a triboelectric charge amount distribution is sharp. It is intended to provide a developer that is uniform and can control the charge amount suitable for the developing system used.

Still another object is a developer that faithfully develops and transfers a latent image, that is, adhesion of toner in the background area at the time of development, that is, no fog or toner scattering around the edge of the latent image, High image density is obtained,
This is to provide a developer having good halftone reproducibility.

Still another object is to provide a developer which maintains the initial characteristics even when the developer is continuously used for a long period of time and does not cause aggregation of toner or change in charging characteristics.

Still another object is to provide a developer that reproduces a stable image that is not affected by changes in temperature and humidity, especially a developer with high transfer efficiency that does not cause scattering or transfer omission during transfer at high humidity and low humidity. In offer.

Still another object is to provide a bright chromatic color developer.

Still another object is to provide a developer having excellent storage stability, which maintains the initial characteristics even after long-term storage.

Still another object is to provide a developer which can be easily cleaned in a cleaning step without causing the electrostatic latent image surface to be soiled, worn or scratched.

Still another object is to provide a developer having good fixing properties, particularly a developer free from problems such as high temperature offset.

[Means and Actions for Solving Problems]

The present invention comprises a binder resin, a colorant (excluding magnetic powder) and a substituted guanidine compound represented by the following general formula (I), and is a positively chargeable non-magnetic toner for developing an electrostatic charge image. It is in.

(In the formula, R ¹ and R ² represent condensed aromatic polycyclic groups and derivatives thereof.) Note that R ¹ and R ² represent the same or different groups.

In order for a compound to exhibit excellent characteristics as a charge control agent for a toner for developing an electrostatic image, it is important that the substance itself has a large triboelectric chargeability and that a large number of the substance are present on the toner surface. In the present invention, when an aromatic condensed polycyclic group is used as a substituent of guanidine, the triboelectric charging ability is generally increased more than that of other guanidine, and
The compatibility dispersibility of guanidine with respect to the resin is improved, and it becomes easy for the particles to uniformly exist on the surface of one toner particle. for that reason,
More than when using other guanidine as a charge control agent,
It is possible to obtain a developer having better environment resistance.

Further, since the substituted guanidine compound according to the present invention is basically a colorless compound, it is effective as a charge control agent for color toner. Furthermore, comparing the image qualities of the images obtained by the toner containing the conventional charge control agent, the one using the substituted guanidine compound according to the present invention as the control agent is excellent in gradation, and the image quality is moist. It is characterized by being able to. Examples of the condensed aromatic polycyclic group in the substituted guanidine compound include condensed polycyclic groups such as naphthyl group, anthryl group and phenanthryl group.

One example of the diarylguanidine that can be used in the present invention is shown below, but the present invention is not limited to the following specific examples.

As a method of incorporating the above compound into the developer, there are a method of adding it inside the developer and a method of adding it externally. When internally added, the amount of these compounds used is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is uniquely limited. It is not limited, but preferably 0.1 to 20 parts by weight (more preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the binder resin.
Parts by weight).

When adding externally, 0.01 to 100 parts by weight of the resin is added.
10 parts by weight is preferred.

Also, a conventionally known charge control agent can be used in combination with the charge control agent of the present invention.

Examples of the colorant used in the present invention include carbon black, lamp black, ultramarine, nigrosine dye, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow G, rhodamine 6G, lake, chalco oil blue, chrome yellow, quinacridone, benzidine. Any conventionally known dyes and pigments such as yellow, rose bengal, triallylmethane dyes, monoazo dyes and disazo dyes may be used alone or in combination.

As the binder resin used in the present invention, polystyrene,
Monopolymers of styrene such as poly-p-chlorostyrene and polyvinyltoluene and their substitution products; styrene-p-chlorostyrene copolymers, styrene-propylene copolymers,
Styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer Coal, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene- Vinyl ethyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene- Maleic acid copolymer Styrene-based copolymers such as styrene-maleic acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, polyacrylic Examples thereof include acid resins, rosins, modified rosins, temperel resins, phenol resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins and paraffin waxes, which can be used alone or in combination.

Further, as the binder resin particularly suitable for pressure fixing, the following can be used alone or in combination.

Polyolefin (low molecular weight polyethylene, low molecular weight polypropylene, polyethylene oxide, polytetrafluoroethylene, etc.), epoxy resin, polyester resin, styrene-butadiene copolymer (monomer ratio 5 to 30:95 to 7)
0), olefin copolymer (ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene-methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer, ethylene-vinyl chloride copolymer, Ethylene-vinyl acetate copolymer, ionomer resin), polyvinylpyrrolidone, ethyl vinyl ether-maleic anhydride copolymer, maleic acid-modified phenol resin, phenol-modified terpene resin.

Further, when the toner of the present invention is used as a two-component developer, it is used as a mixture with carrier powder.

As the carrier that can be used in the present invention, all known carriers can be used, for example, magnetic powder such as iron powder, ferrite powder and nickel powder, glass beads and the like, and those whose surface is treated with resin or the like. And so on.

Further, the toner of the present invention may be mixed with an additive as required. Examples of the additive include lubricants such as Teflon and zinc stearate, abrasives such as cerium oxide and silicon carbide, fluidity imparting agents such as colloidal silica and aluminum oxide, anti-caking agents, or carbon black and tin oxide. A conductivity-imparting agent such as
Alternatively, there are fixing aids such as low molecular weight polyethylene.

To prepare the toner for developing an electrostatic image according to the present invention, the charge control agent according to the present invention is used as a vinyl-based or non-vinyl-based thermoplastic resin and a pigment or dye as a colorant, and if necessary, an additive, etc. Is thoroughly mixed with a ball mill or other mixing machine, and then using a heat kneader such as a heating roll, a kneader or an extruder, a resin or pigment is melted, kneaded and kneaded to make the resins compatible with each other. Are dispersed or dissolved, cooled and solidified, then crushed and classified to have an average particle size of 5 to 20.
It is possible to obtain μ toner.

Alternatively, a method in which the material is dispersed in a binder resin solution and then spray-dried, or a predetermined material is mixed with a monomer to form the binder resin to form an emulsified suspension and then polymerized A method such as a polymerization method for obtaining a toner and a toner manufacturing method can be applied.

Toners produced by these methods can be all developed by a conventionally known means for development to visualize an electrostatic charge image in electrophotography, electrostatic recording, electrostatic printing, etc. It exhibits the following excellent effects regardless of reversal development.

That is, the triboelectric charge amount between the toner particles is uniform, and the control of the electric charge amount is easy. Further, the toner is extremely stable without deteriorating during use so that the triboelectric charge amount does not vary or decrease. For this reason, the above-described phenomena such as fog, toner scattering, contamination of electrophotographic photosensitive materials and copying machines are eliminated, and the toner of the present invention is extremely excellent, so that, for example, toner during storage, which has been a major drawback in the past, It is a toner that can withstand long-term storage without causing phenomena such as aggregation, agglomeration, and low-temperature fluidization, and also has excellent abrasion resistance, fixability, and adhesiveness of toner images.

The excellent effect of such a toner is that when it is used in a repetitive transfer copying system in which the operations of charging, exposing, developing, and transferring are continuously repeated, the effect is further expanded. Further, since there is little color tone disturbance due to the charge control agent, it is possible to form a color image of excellent color when used as a color electrophotographic toner.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto. All parts in the following formulations are parts by weight.

Example 1 Styrene / butyl methacrylate (80/20) copolymer 100 parts Carbon black 5 parts Low molecular weight polyethylene wax 2 parts Compound (I) 2 parts The above materials were well mixed in a blender and then heated to 150 ° C. 2 It was kneaded with a main roll. The kneaded product was allowed to cool naturally, coarsely pulverized with a cutter mill, pulverized with a fine pulverizer using a jet air flow, and further classified with an air classifier to obtain fine powder having a particle size of 5 to 20 μm. .

A developer was prepared by mixing 5 parts of the fine powder with 100 parts of the iron powder carrier having an average particle diameter of 50 to 80 μm.

Then, on the OPC photosensitive member by a conventionally known electrophotographic method,
A negative electrostatic charge image was formed, and this was powder-developed by the magnetic brush method using the above-mentioned developer to form a toner image, which was transferred onto plain paper and heat-fixed. The obtained transferred image had a sufficiently high density, no fog, no toner scattering around the image, and a good image with high resolution was obtained.

Further, at the time of durability, the above-mentioned filming phenomenon related to the toner on the photosensitive member was not observed at all, and no problem in the cleaning process was found. Also, at this time, there was no trouble in the fixing process, at the end of the durability test of 30,000 sheets,
When the fixing device was observed, the roller was not scratched or damaged, and there was almost no stain from the offset toner, so there was no problem in practical use.

Further, when the environmental conditions were 35 ° C. and 85%, the image density was a value almost unchanged from normal temperature and normal humidity, and a clear image was obtained without fogging or scattering.

Next, when a transferred image was obtained at a low temperature and low humidity of 15 ° C. and 10%, the image density was sufficiently high, and solid black was developed and transferred extremely smoothly, and was an excellent image without scattering and hollowing.

Comparative Example 1 A developer was obtained in the same manner as in Example 1 except that 2 parts of ditolylguanidine was used instead of 2 parts of the compound (I), and development, transfer and fixing were performed to obtain an image in the same manner.

Fog was small at room temperature and normal humidity, but the image density was as low as 1.06, and line images were scattered as compared with those in Example 1, and solid black was noticeable.

Example 2 A developer was obtained in the same manner as in Example 1 except that 3 parts of the compound (2) was used instead of 2 parts of the compound (1), and development, transfer and fixing were carried out, and an image was similarly obtained.

Detailed results are shown in Tables 1 and 2, and almost the same satisfactory results as in Example 1 were obtained.

Example 3 A developer was obtained in the same manner as in Example 1 except that 5 parts of the compound (3) was used instead of 2 parts of the compound (1), development, transfer, and
An image was similarly obtained by fixing.

The detailed results are shown in Tables 1 and 2, and almost the same satisfactory results as in Example 1 were obtained.

Example 4 A developer was obtained in the same manner as in Example 1 except that 2 parts of the compound (4) was used instead of 2 parts of the compound (1), development, transfer, and
An image was similarly obtained by fixing.

The detailed results are shown in Tables 1 and 2, and almost the same satisfactory results as in Example 1 were obtained.

Example 5 Styrene / butyl methacrylate (80/20) copolymer 100 parts (weight average molecular weight Mw: about 300,000) Copper phthalocyanine blue pigment 5 parts Low molecular weight polypropylene wax 2 parts Compound (1) 2 parts The above material was blended. After thoroughly mixing with, the mixture was kneaded with two rolls heated to 150 ° C. The kneaded product was allowed to cool naturally, coarsely pulverized with a cutter mill, pulverized with a fine pulverizer using a jet air flow, and further classified with an air classifier to obtain fine powder having a particle size of 5 to 20 μm. .

Next, 100 parts of the fine powder was mixed with 50 g of magnetic particles having a particle diameter of 50 to 80 μm to obtain a developer.

When an image was formed using this developer by the developing method shown in FIG. 1, a good image showing a vivid blue color was obtained, and after 1500 sheets were formed, the toner / carrier was set to 10 g / 50 g. However, almost no change in image density was observed. The main developing method will be described. In FIG. 1, 1 is an electrostatic image carrier, 2 is a toner carrier, 3 is a hopper, 52 is a magnetic brush made of a carrier toner mixture,
Reference numeral 58 is a toner thickness regulating blade, 50 is a fixed magnet, 6 is a developing bias, and 5 is toner.

That is, the magnetic brush 52 formed on the toner carrier 2 is circulated by rotating the toner carrier 2, and the toner in the Hopper 3 is taken in to coat the 2 evenly in a thin layer. Next, the toner carrier 2 and the electrostatic image carrier 1 are opposed to each other with a gap larger than the toner layer thickness, and the toner 5 on
Fly development is performed on the electrostatic image above.

The thickness of the toner layer is controlled by the size of the magnetic brush 52, that is, the amount of magnetic particles and the regulating blade 58. 1 and 2
It is also possible to apply a developing bias of 6 by making the gap between and larger than the thickness of the toner layer.

The evaluation results of each example and comparative example are shown in Tables 1 and 2.

[Effects of the Invention] The effects obtained by the present invention are as follows.

(1) The triboelectric charge amount between the toner particles, between the toner and the carrier, between the toner and the toner carrier such as the sleeve in the case of one-component development is stable, and the triboelectric charge amount distribution is sharp and uniform. , A developer that can control the charge amount suitable for the developing system used.

(2) A developer capable of faithful development and transfer to a latent image, maintaining initial characteristics even when continuously used for a long period of time, and having no toner aggregation and no change in charging characteristics.

(3) A developer that can reproduce a stable image that is not affected by changes in temperature and humidity and that can obtain a bright chromatic image.

(4) It is a developer which is easy to perform a cleaning process that does not stain, rub, or scratch the electrostatic latent image surface and has excellent fixing characteristics, and does not have a problem such as high temperature offset.

[Brief description of drawings]

FIG. 1 is an illustration of an example of a developing device to which the positively chargeable toner according to the present invention can be applied. 1 ... Electrostatic image carrier, 2 ... Toner carrier, 5 ... Toner, 50 ... Magnet, 52 ... Magnetic brush 58 ... Regulating blade.

Claims (1)

[Claims] 1. Binder resin, colorant (excluding magnetic powder)
And a substituted guanidine compound represented by the following general formula (I), which is a positively chargeable non-magnetic toner for developing an electrostatic image. (In the formula, R ¹ and R ² represent an aromatic condensed polycyclic group and its derivative.)